Saturday, 24 March 2012

Human-elephant conflict in southwestern India

Human-wildlife conflict is a rapidly expanding area of research, with conservationists working hard to understand the circumstances under which tensions are highest between people and their wild animal neighbors. A number of factors contribute to rate and intensity of conflict, including population densities of both humans and wildlife, habitat structure, weather, time of year, and animal life histories, to name just a few. As a result, separate assessments are required for each "problem" species in each area at risk; thus, while recent findings about elephant crop raiding behaviors in Africa may be illuminating for managers trying to grapple with similar activities among Asian elephants (Elephas maximus), it is still important for researchers to conduct local assessments in order to fully understand the correlates of conflict in elephant hotspots such as southern India.

(Asian elephants, Elephas maximus)

Indians can petition the government for compensation after crop-raiding and attacks by wildlife, and the resulting paper trail provides information about a number of potential correlates of conflict--including the location, intensity, and frequency of crop raids, the efficacy of deterrents (if any are installed), and the speed and utility of the compensation process. Further, data from the claims can be coupled with meteorological and geographical information in order to provide an indication of whether, and how, wildlife encounters are impacted by weather and distance to animal preserves.

Indian conservationist Sanjay Gubbi recognized the potential of this latent dataset, prompting him to sort through hundreds of reports filed over a 3-year period in and around Nagarhole National Park in southwest India. The park is contiguous with several other important wildlife habitats, including Bandipur National Park, Mudumalai and Waynaard Wildlife Sanctuaries, and several reserved forests; cumulatively, these areas cover about 5,000 square kilometers of prime elephant habitat. Although locals occasionally experience attacks by tigers (Panthera tigris) and crop-raiding by gaur (Bos gaurus), elephants are the major source of stress in the area--accounting for 99.9% of the 1955 crop loss incidents for which the government dispensed compensation during Gubbi's 3-year study period.

Elephants damaged or consumed 26 different types of crop, but five major species bore the brunt of the activity: finger millet (Eleusine coracana), maize (Zea mays), cotton (Gossypium spp.), rice (Oryza sativa), and sugarcane (Saccharum officinarum). The temporal pattern of human-elephant conflicts--peaking between August-November but remaining low throughout the rest of the year--appears to refute the myth that crop-raiding is more common in the dry months because elephants are desperate for food. Rather, conflicts peaked just after the monsoon season, when vegetation should be most lush. These peaks coincide with the ripening of tasty crops such as millet, maize, and rice. Thus, it appears that the elephants may be using their keen sense of smell to detect and target potential food sources when they become available. This may also explain why conflicts were most common in a band 3.1-5 km away from the Nagarhole National Park boundary rather than right next to it, as one might predict: Perhaps the best crops are those several kilometers away, and the elephants use their olfactory prowess to bypass mediocre fields and target only those with the best food.

Although previous researchers have suggested that elephants are particularly fond of sugarcane, Gubbi's results indicated much heavier activity in millet, maize, and rice fields. Thus, he posits that the elephants utilize sugarcane opportunistically when it is encountered near more satisfying crops. Inedible cotton, on the other hand, is probably only damaged when it gets in the way of hungry elephants commuting to nearby fields with tastier products.

(Finger millet, Eleusine coracana)

Conflicts were rare outside of a 6-km band around Nagarhole National Park. Elephant activity was more likely in areas that shared longer borders with protected habitat; conversely, they it was slightly less common in places with more unirrigated land. Overall, most villages (49.3%) suffered only 1-10 conflicts, but a surprising number (36.7%) experienced 11-50. Few saw more than this, though some areas did experience over 100 visits by raiding elephants.
Over the course of the 3-year study period, claimants in these areas received a total of
$52,026 to cover losses resulting from elephant raids; even worse, elephants were responsible for 10 human deaths and 8 injuries. Individual
farmers had to wait an average of 114 days to receive the relatively
small sum of approximately $31 per conflict.

A recently-completed study on elephants in the same region reported only 806 conflicts during a 12-year period--or approximately 67 conflicts per year. This contrasts markedly with the ~652 conflicts per year reported here. Although some of the difference may be the result of an increase in claim filing, it also appears likely that both human and elephant populations have swelled enough to increase the likelihood of unpleasant encounters between the two species. It may be possible to reduce these encounters using simple mitigation techniques such as the installation of fences and ditches around fields, or even high-tech solutions such as chemical sprays that mask the enticing smells of ripening crops.

(Elephant in Nagarhole National Park)

The author feels that his work refutes previous claims about elephant behavior and exposes some suggested management strategies as useless. For instance, elephants do not, as previously believed, fixate on sugarcane fields or irrigated areas; thus, efforts to minimize these near preserves would not likely reduce conflict. Likewise, he says, the animals do not raid crops more during the dry seasons, and so the creation of water holes and the cultivation of fodder crops inside the park would probably just waste precious management resources. Instead, Gubbi recommends erecting physical barriers around park boundaries, incorporating nearby protected areas into the park so they can serve as buffers, and concentrating conflict-prevention efforts on the August-November period when crop raiding is most common. When and if these measures fail, he encourages the government to provide better compensation to farmers, or at least to do so more quickly; this should prevent retaliatory behavior against elephants. Finally, the author also suggests a state-wide study on human-elephant conflicts in order to provide more perspective so that long-term elephant management plans can be coordinated throughout the country.

Thanks to the following websites for providing the images used in this post:
http://petpicks.wordpress.com/2010/11/18/elephants/20090812-asian-elephant-thailand/
http://www.maps-india.com/karnataka/wildlife/nagarahole-national-park.html
http://en.wikipedia.org/wiki/Eleusine_coracana
http://en.wikipedia.org/wiki/File:Elephant_in_Nagarhole_National_Park.jpg

Who is the "Anthrophysist"?

I am a biologist who studies the ways in which anthropogenic disturbance impacts animals (especially birds). I hope that the results of my work, and the work of other researchers like me, can help humans learn how to coexist more peacefully with wildlife. I am also interested in the role that nature has played in shaping human cultures around the world and over the centuries. Although this blog will predominantly focus on scientific research, I hope to occasionally profile some anthropological work as well, in order to better highlight the interconnectedness of humans ("anthro") and nature ("physis").